Polaronic nature of a muonium-related paramagnetic center in SrTiO${}_3$

Abstract

The hyperfine features and thermal stability of a muonium (Mu)-related paramagnetic center were investigated in the SrTiO${}_3$ perovskite titanate via muon spin rotation spectroscopy. The hyperfine coupling tensor of the paramagnetic center was found to have prominent dipolar characteristics, indicating that the electron spin density is dominantly distributed on a Ti site to form a small polaron near an ionized Mu${}^{+}$ donor. Based on a hydrogen-Mu analogy, interstitial hydrogen is also expected to form such a polaronic center in the dilute doping limit. The small activation energy of 30(3) meV found for the thermal dissociation of the Mu${}^{+}$-polaron complex suggests that the strain energy required to distort the lattice is comparable to the electronic energy gained by localizing the electron.

arXiv commentThe following article has been accepted by Applied Physics Letters. After it is published, it will be found at https://aip.scitation.org/journal/apl

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• Ambipolar Property of Isolated Hydrogen in Oxide Materials Revealed by Muon
• Negatively Charged Muonium and Related Centers in Solids
• Hydrogen-Ti${}^{3+}$ Complex as a Possible Origin of Localized Electron Behavior in Hydrogen-Irradiated SrTiO${}_3$
• Nano-scale dynamics of hydrogen in VO${}_2$ studied by $\mu$SR
• Muon spin relaxation in mixed perovskite (LaAlO${}_3$)${}_x$(SrAl${}_{0.5}$Ta${}_{0.5}$O${}_3$)${}_{1-x}$ with $x\simeq 0.3$
• Local electronic structure of interstitial hydrogen in MgH${}_2$ inferred from muon study
• Electron $g$-value comparison of paramagnetic muonium and hydrogen centers in rutile TiO${}_2$
• Local electronic structure and dynamics of hydrogen in ${\text{CeO}}_2$